Capacitors are prevalent in a wide variety of industries and applications. A known problem with standard capacitors, and with high voltage capacitors in particular, is the generation of corona, sometimes referred to as corona discharge, which may lead to failure of the dielectric in the capacitor and, thus, failure of the capacitor. Another problem with standard high voltage capacitors is the generation of heat due to corona, due to high frequency operation of the capacitor, or for some other reason; heat may cause deterioration of the capacitor dielectric, also leading to capacitor failure.
Corona and the accompanying generation of ultra-violet (UV) light may degrade the dielectric used in capacitors, also leading to premature failure. For example, corona discharge and UV light may cause the crystallization of glass and the breakdown of certain polymers used in the manufacture of dielectrics for capacitors.
To reduce corona generation and its accompanying negative effects, it is known in the art that a capacitor may be immersed in a fluid (e.g., oil) to exclude ionizable fluid or gases from the areas and/or surfaces subject to corona generation. A fluid such as oil also may be used to cool a capacitor. The oil also may be used as a self-healing component to eliminate air bubbles; eliminating air bubbles avoids the generation of corona.
One problem with using a liquid (e.g., oil) to cool capacitors and to prevent corona generation, is that the addition of fluid increases the weight of the capacitor. Another problem results from the need to stabilize the fluid to prevent breakdown and/or oxidation of the fluid. One method of stabilization has been achieved through the addition of polychlorinated biphenyls (PCB's) to the oil. The perceived negative health and environmental implications of these additions have made oil leakage from such a capacitor and disposal of the oil an additional concern.
There is an increasing need in the art for an alternative method of cooling capacitors.
In some instances, there also is a need for reducing and/or preventing corona discharge in capacitors and the associated negative effects.
There is a need for inexpensive and environmentally friendly self-healing dielectric for capacitors.